As an enhancement shaman, the last time I was afraid of taking on a mob solo was the third grade. With Bloodlusted wolves at my back, Windfury in my hand, and the massive power of instant Greater Healing Waves every 10 or so seconds, soloing was a breeze. Chillmaw? Soloed him daily. Attumen the Huntsman? Weekly. Gamom, level 5 elite neutral tauren? Every chance I got (until Blizzard force fed him "performance" pills).
Going into the Cataclysm beta, if Blizzard wrote a post on its forums warning that solo mobs will actually start threatening my life, I would have written it off as a Public Service Announcement for those pesky mages and rogues who had to worry about things like dying in leveling content. Actually, when Blizzard did write that post on its forums, I wrote it off as a pesky PSA for pures with no self-heals. And then I died. I died quite a bit ... until I stopped trying to AoE grind.
Mobs in a Deathwing-infused world hurt. Moreover, they have a lot of hit points. They're no longer just problems for squishy mages and hardy but heal-less warriors. If you pull too many mobs, don't kill fleeing mobs before they warn their friends, or attempt to play chicken with the Whale Shark, you will die. This post will attempt to help you with surviving the first two. For the third, you're on your own.